Spark plugs



Oct. 18, 1960 R. J. DUTTERER SPARK PLUGS Filed Sept. 18. '1959 INVENTOR. Rex d Duf/erer BY ,4 TTOIR N s x United States Patent SPARK PLUGS Rex J. Dutterer, Hastings, Mich., assignor to Hastings Manufacturing Company, Hastings, Mich., a corporation of Michigan Filed Sept. 18, 1959, Ser. No. 840,954

4 Claims. (Cl. 313143) This invention relates to improvements in spark plugs. The main objects of this invention are:

First, to provide a spark plug which is highly eflicient from the sparking angle and maintains its efiiciency over a long use period.

Second, to provide a spark plug with relatively few parts which may be very economically produced and assembled.

Third, to provide a spark plug having these advantages in which the electrodes are of relatively large dimensions and subject to little wear or attrition in use, and one in which the electrodes are supported in fixed relation relative to each other so that they cannot be tampered with or adjusted in a manner that might render the spark plug efficient.

Further objects and advantages will appear from the following description. A preferred embodiment of my invention is illustrated in the accompanying drawing in which Figure l is a side elevation view of a spark plug embodying my invention, partially broken away to illustrate details thereof, the spark plug being illustrated as mounted on a combustion chamber wall, a fragment of which is conventionally illustrated.

Figure 2 is an enlarged inner end elevation with a portion of one of the ground electrodes broken away.

Figure 3 is a fragmentary View partially in section of a line corresponding to lines 3-3 of Figure 2.

Figure 4 is a fragmentary inner end view of a spark plug embodying my invention which is provided with three ground electrodes.

It should be understood that all of the views are considerably enlarged as compared to the commercial embodiment, this being done in the interest of clearness and convenience in illustration, but the parts are shown in approximately their proper proportions relative to each other. These proportions, however, may be varied to meet varying use conditions. In the accompanying drawings 1 represents a wall of an internal combustion engine having a threaded bore 2. The embodiment of my spark plug illustrated comprises a metallic shell 3, the tubular insulator 4, and the live or insulated electrode 5 which in the embodiment illustrated is in the form of a cylindrical rod-like member; that is, it is desirable to use rod-like stock of uniform diameter. The electrode 5 is disposed with its faced inner end or tip 6 slightly projecting from the inner end 7 of the insulator. The shell is provided with a threaded portion 8 dimensioned to be threaded into the threaded opening 2 in the wall of the cylinder. The shell is provided with a knurled portion 9 and a hexagonal portion 10, but these features form no part of this invention and are more or less standardized. The insulated electrode projects at 11 from the insulator portion 12 for the attachment of a wire thereto. The shell terminates in or is provided with integral angularly spaced ground electrodes 13, the tips 14 of which are disposed in or substantially in the plane of the inner end of the insulator. These ground electrodes are segmental and are angularly spaced, their inner faces 15 being spaced from the insulator as is It will be noted that these ground electrodes project.

from the threaded body portion or wall engaging portion of. the shell so that they project slightly into the combustion chamber. The angular spacing of these elec-. trodes is such that no cross sparking can result, and further than that the space between the electrodes is open to the scavenging chamber 18 which surrounds the insulator above the ground electrodes, and is open to the spaces between the ground electrodes and the insulator. The result is that there is little tendency for the electrodes to accumulate carbon, but in the event that it should accumulate as a result of starting conditions or fuel conditions or the like, the electrodes are effectively scavenged in normal driving or use conditions. The ground electrodes, being formed as integral parts of the shell, are not bendable or manipulatable by installers or users or repair people or the like; and a relatively large sparking surface or area is provided. The slot-like space between the ground electrodes and the insulator opening to the scavenging chamber permits the passage of gases under use conditions, which keeps the sparking areas clean, which results in maximum efficiency of the spark plugs in use. In the embodiment shown on Figure 4 three ground electrodes 19 are illustrated, these being angularly and uniformly spaced, but not disposed in direct opposed relation as in the embodiment shown in Figures 1, 2, and 3. It should, however, be noted that in this embodiment the ground electrodes are substantially spaced relative to each other so that there are substantial openings to the scavenging chamber 18 between them.

The embodiments of my invention illustrated are high- 1y practical and desirable commercial embodiments. I have not attempted to illustrate or describe other embodiments or adaptations, as it is believed that the disclosure thereof would enable those skilled in the art to embody or adapt my invention as might be desired.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A spark plug including a metallic shell, a tubular insulator supportedly disposed within the shell, and an insulated electrode disposed within the insulator, the inner end of the insulated electrode being cylindrical, closely fitting the insulator and having a fiat-faced tip portion projecting from but disposed closely adjacent to the inner end of the insulator, said shell having integral and angularly spaced inwardly converging segmental terminal portions at its inner end, disposed in opposed relation, constituting ground electrodes, the tip faces of which are substantially fiat and are positioned in substantially the plane of the inner end of said insulator, the spacing of said electrodes exceeding the width thereof; the inner surfaces of said ground electrodes being curved and being concentric to but radially spaced from said insulated electrode, a portion of the shell above said ground electrodes being substantially spaced from said insulator providing a scavenging chamber above said ground electrodes opening between and at the juncture of said ground electrodes with said shell.

2. A spark plug including a metallic shell, a tubular insulator supportedly disposed within the shell, and an insulated electrode disposed within the insulator, the inner end of the insulated electrode being cylindrical, closely fitting the insulator and having a tip portion project- Patented Oct. 18, 1960 ing from but disposed closely adjacent to the inner end of the insulator, said shell having integral and angularly spaced inwardly converging segmental terminal portions at its inner end disposed in laterally spaced relation constituting ground electrodes the spaces between the electrodes being approximately that of the width of the electrodes, the inner surfaces of said ground electrodes being radially spaced from said insulated electrode, a portion of the shell above said ground electrodes being substantially spaced from said insulator providing a scavenging chamber above said ground electrodes opening between and at the juncture of said ground electrodes with said shell.

3. A spark plug including a metallic shell, a tubular insulator supportedly disposed within the shell, and an insulated electrode disposed within the insulator, the inner end of the insulated electrode being cylindrical, closely fitting the insulator and having a tip portion projecting from but disposed closely adjacent to the inner end of the insulator, said shell having integral and angularly spaced inwardly converging segmental portions at its inner end disposed in laterally spaced relation, constituting ground electrodes the spaces between the electrodes being approximately that of the width of the electrodes, the inner surfaces of said ground electrodes being radially spaced from said insulated electrode, a

portion of the shell above said ground electrodes being substantially spaced from said insulator providing a scavenging chamber above said ground electrodes opening between and at the juncture of said electrodes with said shell.

4. A spark plug including a metallic shell, a cylindrical tubular insulator supportedly disposed within the shell, and a cylindrical electrode supportedly disposed within and centrally of said insulator with its inner end projecting from but closely adjacent to the inner end of the insulator, the shell having integral angularly spaced inwardly converging segmental terminal portions constituting ground electrodes the spaces between the electrodes being approximately that of the Width of the electrodes, said ground electrodes being of curved cross section and disposed with their inner surfaces radially spaced from said insulator, a portion of the shell above said ground electrodes being spaced from said insulator providing a scavenging chamber opening between and at 20 the juncture of said electrodes with said shell.

References Cited in the file of this patent UNITED STATES PATENTS 

